Problem: Simplify the following expression. $ (7 + (10 - 5 \times 9)) \times 9 $
$ = (7 + (10 - 45)) \times 9 $ $ = (7 + (-35)) \times 9 $ $ = (7 - 35) \times 9 $ $ = (-28) \times 9 $ $ = -28 \times 9 $ $ = -252 $